Door operating apparatus



NOV. 6, 1934. E G PARWN 1,979,569

DOOR OPERAT ING APPARATUS Filed Sept. l5, 1935 @WM ATTORNE Patented Nov. 6, 1934 UNITED STATES PATENTQOFFICE Eaw'na o. rai-vm, nonne, N. J., mmm to National Pneumatic Company, New York, N. Y.. a corporation oi' West Virginia Application September 15, 1933, Serial No. 689.682 2 Claims. (Cl. 268-53) This invention relates in general to improve- 6 and a carrier 4 in which are mounted a pluments in door operating apparatus and more rality of mercury switches disposed in the proper particularly to control circuits and mechanism angular relationship to produce a polyphase alfor electric motor driven door operating apparaternating current from a direct current source. tus as applied on vehicles. 'I'he details of construction oi' this converter 60 An important object of this invention is to form no part of this invention and may be found provide a control system for door operating apin my copending application Serial No. 619,844. paratus employing a linear induction motor filed June 29, 1932, for Door operating apparafor moving the door. tus. The general combination of a rotary con- A further object of this invention is to proverter mercury switch arrangement for trans- 65 vide a control circuit in which the control switch forming direct current into alternating current takes two positions, namely, door opening and is well known in a number of forms in the art door closed positions. The door or the like to be operated is indicated A still further object oi this invention is to diagrammatically at 1 and is shown provided l employ in connection with such apparatus door with a metal bar 2 secured into and extending 70 operated switches for automatically deenergizing transversely thereof. This bar may be made of the circuit when the door is fully opened and magnetic material but not necessarily since alufully closed and further for introducing a reminum, copper and the like are practicable. sistance into the circuit near the end of the This bar 2 provides the armature or equivalent 80 stroke of the door in either direction to cause of the rotor of an induction motor. The field 75 the motor to slow down. 3 of the motor is illustrated diagrammatically These and many other objects as willappear and consists of a magnetizable core having a from the following disclosure are secured by distributed polyphase winding mounted therein. means of this invention. The details of construction of this motor may 'I'his invention resides substantially in the likewise be found in my above noted copending 80 combination, construction, arrangement, relaapplication. They do not form by themselves tive location oi' parts and circuital connections, any part of this invention. Here again, linear all as will be described in full detail hereinafter. induction motors in a number of forms are wel]` Referring to the drawing: known in the art.

Fig. l is a diagrammatic view of the circuit In the present case the winding of the stator 85 connections and apparatus comprising the in- 3 is a two-phase winding connected by wires to vention. the slip rings of the converter. When the stator In the application of linear induction motors is energized with alternating current a linearly to the duty of opening and closing doors and traveling electric eld is created which as will the like it has been found highly desirable to be apparent to those skilled in the art causes the 90 provide an automatically operating system in bar 2 to move in accordance with the direction which the motor is slowed down near the end of travel of the eld to either open or close of its opening and closing strokes so that the the door. door will not come to a stop too abruptly. The The control circuits for this mechanism will prime purpose of this invention is to provide now be described. At 7 and 9 are shown limit 95 such a. system. switches positioned so as to be engaged by the As illustrated in the drawing, the system of door at the two extremes of its movement. this invention employs apparatus for convert- When the door is closed, switch 7 is closed ing direct current to alternating current, aland switch 9 is open. As the door begins to though as is apparent the invention is in no open switch 9 closes and as the door reaches 10o sense limited to such an energizing source. In the end of its opening movement switch 7 is the operation of doors and the like by linear inengaged thereby and opened. At 8 and 10 are duction motors, it is necessary to have an opshown knock out switches likewise operated by erating alternating current of low frequency the door. When the door is closed switch l0 of the order of ten cycles per second and lower. is closed and switch 8 is open. As the door 105 Such low frequencies are desirable in order that opens switch 10 is opened and switch 8 is closed. the door not be operated at too high speeds. The Whereas switches 7 and 9 are operated by the converter comprises a direct current driving modoor as it reaches the end of its stroke in either tor5 having independent eld and armature condirection, switches 8 and l0 are positioned so .55 nections. Thismotor drives aslip ring assembly as to be operated as the door nears the end 11o of its stroke but before it reaches the limits thereof.

At 12 is a suitable current source which has one terminal grounded and the other terminal connected by wire 13 through resistance 14 to the upper contact of switch 7 and the upper contact of switch 9. At l1 is the door control switch, comprising a drum having three contacts thereon and two sets of nve contact fingers. The lower contact' of switch 7 is connected by wire 15 to contact finger 16. The lower contact of switch 9 is connected by wire 40 to contact finger 30. The upper contact finger of limit switch 10 is connected by wire 35 to contact finger 36. The upper contact finger of limit switch 8 is connected by wire 39 to contact finger 37. Contact ngers 25 and 27 are connected together by wire 26 which is grounded. Contact fingers 20 and 21 are connected together by wire 23 and connected by wire 24 to contact finger 19 and to one terminal of the armature winding of motor 5. The other terminal of the armature winding is connected by wire 31 through slow down, resistance 33 and wire 34 to the lower contact fingers of limit switches 8 and 10. Wire 31 is connected by wire 32 to contact finger 29. The drum of switch 11 is provided with the three contacts 22, 18 and 28, as shown. This switch is in door opening position as shown in the drawing.

The wires 24 and 31 are connected in parallel. into a relay winding 41 which when magnetized closes switch 42. At 43 and 47 are the direct current supply wires which may be energized from any suitable source such as the third rail of a railway system. Wire 43 is connected to the switch arm of switch 42. The contact of this switch is connected by wire 44 to one terminal of the field winding of the motor 5 and to one of the slip rings of the converter. Wire 47 is connected through the lock winding 46 to wire 45 which is connected to another slip ring of the converter and by wire 48 to the other terminal of the field winding of motor 5. The lock represented diagrammatically at 46 may be of any well known type which is in door-locking position when the winding 46 is deenergized and which is moved to unlocked position when the winding is energized.

The operation of this circuit will now be given, it being remembered that the control switch 11 is in door opening position. Current flows from the source 12 through wire 13 and resistance 14 to switch 7 which is closed. From this switch. the current flows through wire 15, contact nger 16, contact 18, contact finger 19, wire 24, the armature winding of motor 5, wire 31, wire 32, contact nger 29, contact 28, contact finger 27, wire 26 and thence through ground back to the source l2. This causes the energization of the armature of motor 5 as well as the relay winding 41. Switch 42 is thus closed so that current is supplied from the direct current source as follows. Through wire 43, switch 42, field winding of motor 5, wire 48, wire 45, lock winding 46 and thence back to the current source through wire 47. At the same time current is supplied to the direct current slip rings of the converter which are connected in parallel to the field winding of the motor, through the wires 44 and 48.

The energization of lock winding 46 causes the lock to move to unlocked position. Current is supplied from the direct current source to the converter as well as to the field of the motor the armature of which source l2. It is apparent that the source 12 and the direct current source to which wires 43 and 47 are connected may be one and the same source.

The energization of motor 5 causes the operation of the converter with the result that polyphase alternating current is supplied to motor 3 to cause the door to open. As the door begins to move, switch 9 closes, and as the door arrives within a pre-determined distance of its full open position, switch 8 is closed; in the meantime, switch 10 has opened. Upon the closing of Switchs, resistance 33 is cut into the armature circuit as follows. Current flows from wire 24 to contact finger 20 through wire 23, contact finger 21, contact 22, contact finger 37, wire 39, switch 8, wire 34, resistance 33. back to wire 31. Thus, resistance 33 is connected across the armature circuit through switch 8 with the result that motor 5 is slowed down slowing down the converter, and lowering the frequency of the alternating current relayed to the stator 3. The door then continues to open at the slower speed until it reaches the full open position at which time switch 7 is opened deenergizing the armature of motor 5 and winding 41. Switch 42 then opens, opening the direct current circuit. It will be remembered now that switch 9 is closed, switch 10 is open, switch 8 is closed and switch 7 is open. To close the door, the control switch is moved to its door closing position so that contact 22 now bridges contact fingers 20 and 36, contact 18 bridges contact fingers 30 and 29 and contact 28 bridges contact fingers 19 and 25. 'Ihe circuits for door closing operation may now be traced as before for reverse energization of motor 5. As the door arrives within a predetermined distance of its closed position, resistance 33 is again connected into the armature circuit to cause the door to move slowly to fully closed position without slamming and without danger of injury to persons who might be in the doorway. As the door fully closes switch 9 is open, switch 7 having closed as the door began to close. In the meantime, and at the proper time, switch 8 has opened.

From the above description it will be apparent that this invention resides in certain principles of construction and operation which may be embodied in other physical forms and carried out in other ways by those skilled in the art without departing from the scope thereof. I do not, therefore, desire to be strictly limited to the disclosure as given for purposes of illustration but rather to the scope of the appended claims.

What I seek by United States Letters Patent 1. In a system of the type described, the combination comprising a door, a linear induction motor for operating the door having its armature secured to the door and its field supported adjacent the armature as it moves with the door, said field being wound so that when energized with alternating current its magnetic field travels linearly, means for supplying alternating current to said motor to cause the magnetic eld to [travel in either direction to open or close the door, and means for reducing the frequency of the alternating current supplied to the motor as the door nears the end of its stroke in either direction to reduce the linear speed of the travel of the magnetic eld of the motor, whereby the is energized from the door is slowed down near the end of its stroke in either direction.

2. In-a door operating apparatus, the combination comprising a door or the like. an alter- 5 nating current linear induction motor for operating the door in either direction, means for supplying alternating current to said motor, a control switch for energizing the motor for operation ot the door in either direction, and

means in said circuit and controlled by said door for reducing the frequency of the alternating current supplied to the motor when the door arrives within a predetermined distance of its full open or closed position, whereby the speed of linear movement of the magnetic eld o! the motor is reduced and the door nishes its stroke at a reduced speed.

EDWARD G. PARVIN. 

